More than six weeks after nearly 3,300 members voted to change the cooperative's charter to a mutual bank, Monterey Credit Union has filed with the California Department of Business Oversight for that conversion.

Staring down shrinking margins and the confusing moniker “credit union,” some have gotten creative with their fields of membership. This is not a particularly new phenomenon but one that has garnered attention from an L.A. blogger who was just looking for a credit union to join. She’s had a great...